In recent years, fuel cell stack have attracted attention due to efficient use of energy resources and environmental problems.
Patent Literature 1 discloses a fuel cell stack that includes a solid electrolyte layer, an anode, and a cathode which disposed opposite to the anode with the solid electrolyte layer in-between as a reference. The solid electrolyte layer of this fuel cell employs a material formed by a solid solution of a rare earth metal in cerium oxide.